Radio Frequency Identification (RFID) tags are small integrated circuits (ICs) connected to an antenna, which can respond to an interrogating RF signal with simple identifying information, or with more complex signals depending on the size of the IC. RFID technology does not require contact or line of sight for communication. Radio Frequency Identification (RFID) technology is now economically viable and is deployed in more and more commercial and industrial applications. For example, RFID technology is now widely used for tags on items in warehouses, shops, ID or access cards, etc. In addition, RFID technology has been introduced in the payment card industry (e.g., by MasterCard, American Express and Visa) in the form of “contactless” payment or credit cards embedded with RFID tags. These contactless payment cards can be used to make electronic payment transactions via radio communication with an RFID-enabled payment terminal. The contactless payment cards can provide consumers with simple, fast and convenient ways to pay for goods and services, for example, in retail establishments, stores or supermarkets.
Several RFID technologies are available for use in contactless payment cards and card readers/terminals. Contactless cards use proximity couplers to get information to and from the card's chip. An antenna is wound around the circumference of the card and activated when the card is radiated in a specific distance from the coupler. The configuration of the card's antenna and the coupler facilitate connected states from a couple of centimeters to a couple of feet. The bidirectional transmission is encoded and can be encrypted by using a combination of a card vendor's hard-coded chip algorithms; randomly generated session numbers; and the cardholder's certificate, secret key, or personal identification number (PIN). The sophistication of the connection can facilitate separate and discrete connections with multiple cards should they be within range of the coupler.
For contactless payment card systems to be economically viable and to gain commercial acceptance, the contactless payment cards must be interoperable at all or most RFID-enabled payment terminals, even when the cards and terminals have technological features that are proprietary to specific card providers/issuers, vendors or terminal manufacturers. Industry-wide interoperability is desirable. Towards this end, industry standards organizations and groups (e.g., International Organization for Standards (ISO) and International Electro Technical Committee (IEC)) have formulated voluntary industry standards for implementation of contactless payment technologies. Three such exemplary standards which have been defined by ISO/IEC are the ISO/IEC 10536, ISO/IEC 14443, and ISO/IEC 15693 standards applicable to Close Coupling, Proximity and Vicinity cards, respectively.
The physical characteristics of the contactless cards are based on the earlier ISO 7816-1 Standard for integrated circuit cards. ISO 7816-1 Standard limits the physical size of the contactless cards. A standard card size is the ID-1 size: (85.6 mm×54.0 mm×76 mm). This is the same size as a bank credit card. The ISO standards include accommodation of exposure limits for a number of electromagnetic phenomena such as X-rays, UV light, electromagnetic fields, static electrical fields, and ambient temperature of the card. Furthermore, the ISO standards defines the mechanical characteristics of a card when it is bent or flexed. This is to make sure that a plastic card with embedded chip and antenna is manufactured in a manner, which ensures acceptable operation over the expected lifetime of the card.
Commercially deployed contactless payment cards also may include features such as magnetic stripes and embossed lettering, so that the cards are operable with legacy payment-by-card infrastructure such as magnetic stripe card readers and embossed card paper imprinters that still in use in the field. Embossing allows for textual information or designs on the card to be transferred to paper by using a simple and inexpensive device. ISO 7811 specifies the embossed marks, covering their form, size, embossing height, and positioning. Use of magnetic stripe technology advantageously reduces the surfeit of paper documents associated with embossing. ISO 7811 also specifies the properties of the magnetic stripe, coding techniques, and positioning.
Consideration is now being given to improving the design of contactless payment cards. In particular attention is being directed to the design of card antennas. Card antennas that are immune or less susceptible to damage in card fabrication, and from expected wear and tear are desirable.